As computer, electronic and communication technologies are rapidly developed, various wireless communication services using wireless networks have been provided. Accordingly, there is a tendency for services provided in mobile communication systems using wireless networks to develop into multimedia communication services for transmitting circuit data, packet data and others, in addition to voice services. In general, mobile communication devices, which include mobile phones, smart phones, PDAs and so on, are capable of conducting voice and data communication through mobile communication networks.
In addition, mobile communication devices provided with a short-distance communication module like an infrared sensor (IrDa) or Bluetooth are capable of transmitting and receiving specific data (images and/or audio) between the mobile communication devices without using mobile communication networks.
Recently, there has been an attempt to use sound as a communication means. In this regard, Korean Patent Application Publication No. 2007-0035552 describes providing a coupon or an authentication code to a wireless terminal by using sound data.